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Lee HK, Jang WY, Kim YH. Extracellular production of a thermostable Cellvibrio endolytic β-agarase in Escherichia coli for agarose liquefaction. AMB Express 2023; 13:42. [PMID: 37145239 PMCID: PMC10163192 DOI: 10.1186/s13568-023-01551-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 04/20/2023] [Indexed: 05/06/2023] Open
Abstract
Four GH16 family β-agarases (GH16A, GH16B, GH16C, and GH16D), originated from an agarolytic bacterium Cellvibrio sp. KY-GH-1, were expressed in an Escherichia coli system and their activities were compared. Only GH16B (597 amino acids, 63.8 kDa), with N-terminal 22-amino acid signal sequence, was secreted into the culture supernatant and demonstrated a robust endolytic agarose hydrolyzing activity for producing neoagarotetraose (NA4) and neoagarohexaose (NA6) as end products. The optimal temperature and pH for the enzyme activity were 50 °C and 7.0, respectively. The enzyme was stable up to 50 °C and over a pH range of 5.0-8.0. The kinetic parameters, including Km, Vmax, kcat, and kcat/Km, of GH16B β-agarases for agarose were 14.40 mg/mL, 542.0 U/mg, 576.3 s-1, and 4.80 × 106 s-1 M-1, respectively. The addition of 1 mM MnCl2 and 15 mM tris(2-carboxyethyl)phosphine enhanced the enzymatic activity. When agarose or neoagaro-oligosaccharides were used as substrates, the end products of enzymatic catalysis were NA4 and NA6, whereas agaropentaose was produced along with NA4 and NA6 when agaro-oligosaccharides were used as substrates. Treatment of 9%[w/v] melted agarose with the enzyme (1.6 µg/mL) under continuous magnetic stirring at 50 °C for 14 h resulted in efficient agarose liquefaction into NA4 and NA6. Purification of NA4 and NA6 from the enzymatic hydrolysate (9%[w/v] agarose, 20 mL) via Sephadex G-15 column chromatography yielded ~ 650 mg NA4/~ 900 mg NA6 (i.e., ~ 85.3% of the theoretical maximum yield). These findings suggest that the recombinant thermostable GH16B β-agarase is useful for agarose liquefaction to produce NA4 and NA6.
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Affiliation(s)
- Hee Kyoung Lee
- Laboratory of Immunobiology, School of Life Science and Biotechnology, College of Natural Sciences, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, Republic of Korea
| | - Won Young Jang
- Laboratory of Immunobiology, School of Life Science and Biotechnology, College of Natural Sciences, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, Republic of Korea
| | - Young Ho Kim
- Laboratory of Immunobiology, School of Life Science and Biotechnology, College of Natural Sciences, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu, Republic of Korea.
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Xu J, Xu R, Jia M, Su Y, Zhu W. Metatranscriptomic analysis of colonic microbiota's functional response to different dietary fibers in growing pigs. Anim Microbiome 2021; 3:45. [PMID: 34217374 PMCID: PMC8254964 DOI: 10.1186/s42523-021-00108-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 06/23/2021] [Indexed: 01/30/2023] Open
Abstract
Background Dietary fibers are widely considered to be beneficial to health as they produce nutrients through gut microbial fermentation while facilitating weight management and boosting gut health. To date, the gene expression profiles of the carbohydrate active enzymes (CAZymes) that respond to different types of fibers (raw potato starch, RPS; inulin, INU; pectin, PEC) in the gut microbes of pigs are not well understood. Therefore, we investigated the functional response of colonic microbiota to different dietary fibers in pigs through metatranscriptomic analysis. Results The results showed that the microbial composition and CAZyme structure of the three experimental groups changed significantly compared with the control group (CON). Based on a comparative analysis with the control diet, RPS increased the abundance of Parabacteroides, Ruminococcus, Faecalibacterium and Alloprevotella but decreased Sutterella; INU increased the relative abundance of Fusobacterium and Rhodococcus but decreased Bacillus; and PEC increased the relative abundance of the Streptococcus and Bacteroidetes groups but decreased Clostridium, Clostridioides, Intestinibacter, Gemmiger, Muribaculum and Vibrio. The gene expression of CAZymes GH8, GH14, GH24, GH38, GT14, GT31, GT77 and GT91 downregulated but that of GH77, GH97, GT3, GT10 and GT27 upregulated in the RPS diet group; the gene expression of AA4, AA7, GH14, GH15, GH24, GH26, GH27, GH38, GH101, GT26, GT27 and GT38 downregulated in the INU group; and the gene expression of PL4, AA1, GT32, GH18, GH37, GH101 and GH112 downregulated but that of CE14, AA3, AA12, GH5, GH102 and GH103 upregulated in the PEC group. Compared with the RPS and INU groups, the composition of colonic microbiota in the PEC group exhibited more diverse changes with the variation of CAZymes and Streptococcus as the main contributor to CBM61, which greatly promoted the digestion of pectin. Conclusion The results of this exploratory study provided a comprehensive overview of the effects of different fibers on nutrient digestibility, gut microbiota and CAZymes in pig colon, which will furnish new insights into the impacts of the use of dietary fibers on animal and human health. Supplementary Information The online version contains supplementary material available at 10.1186/s42523-021-00108-1.
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Affiliation(s)
- Jie Xu
- Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China.,National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing, 210095, China
| | - Rongying Xu
- Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China.,National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing, 210095, China
| | - Menglan Jia
- Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China.,National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yong Su
- Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China. .,National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing, 210095, China.
| | - Weiyun Zhu
- Laboratory of Gastrointestinal Microbiology, Jiangsu Key Laboratory of Gastrointestinal Nutrition and Animal Health, College of Animal Science and Technology, Nanjing Agricultural University, Nanjing, 210095, China.,National Center for International Research on Animal Gut Nutrition, Nanjing Agricultural University, Nanjing, 210095, China
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Jang WY, Kwon MJ, Kim KY, Kim YH. Enzymatic characterization of a novel recombinant 1,3-α-3,6-anhydro-L-galactosidase specific for neoagarobiose hydrolysis into monosaccharides. Appl Microbiol Biotechnol 2021; 105:4621-4634. [PMID: 34057561 DOI: 10.1007/s00253-021-11341-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 04/28/2021] [Accepted: 05/09/2021] [Indexed: 11/28/2022]
Abstract
Two GH117 family α-neoagarobiose hydrolases (GH117A α-NABH and GH117B α-NABH) from the freshwater agar-degrading Cellvibrio sp. KY-GH-1 were expressed and purified as recombinant His-tagged proteins using an Escherichia coli expression system to compare activities. The amino acid sequence of GH117A α-NABH (364 amino acids, 40.9 kDa) showed 35% identity with that of GH117B α-NABH (392 amino acids, 44.2 kDa). GH117A α-NABH, but not GH117B α-NABH, could hydrolyze neoagarobiose (NA2) into monosaccharides 3,6-anhydro-L-galactose (L-AHG) and D-galactose. The presence of GH117A α-NABH homologues in all of the agar-degrading bacteria aligned suggests that GH117A α-NABH hydrolyzing NA2 into L-AHG and D-galactose is an essential component of the agar-degrading enzyme machinery. For GH117A α-NABH-catalyzed hydrolysis, NA2 was the sole substrate among various neoagaro-oligosaccharides (NA2~NA18). GH117A α-NABH appeared to exist as a dimer, and optimal enzymatic temperature and pH were 35 °C and 7.5, respectively. GH117A α-NABH was stable up to 35 °C and at pH 7.5 and unstable beyond 35 °C and outside pH 7.0~7.5. The kinetic parameters Km, Vmax, kcat, and kcat/Km for NA2 were 16.0 mM, 20.8 U/mg, 14.2 s-1, and 8.9 × 102 s-1 M-1, respectively. Combined addition of 5 mM MnSO4 and 10 mM tris(2-carboxyethyl)phosphine enhanced the enzyme activity by 2.4-fold. The enzyme-mediated hydrolysis of 5.0% NA2 into monosaccharide and purification of L-AHG from hydrolysis products by Sephadex G-10 column chromatography recovered ~ 192 mg L-AHG from 400 mg NA2 (~ 92% of the theoretical maximum yield). These results indicate that the recombinant GH117A α-NABH is NA2-specific and useful to produce L-AHG from NA2. KEY POINTS: • Recombinant GH117A α-NABH (364 aa, 40.9 kDa) purified from E. coli forms a dimer. • The enzyme hydrolyzes only NA2 among various neoagaro-oligosaccharides (NA2~NA18). • The enzyme completely hydrolyzes up to 5% NA2 into monomers under optimal conditions.
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Affiliation(s)
- Won Young Jang
- Laboratory of Immunobiology, School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Mi Jung Kwon
- Laboratory of Immunobiology, School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Ki Yun Kim
- Laboratory of Immunobiology, School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Young Ho Kim
- Laboratory of Immunobiology, School of Life Sciences, BK21 FOUR KNU Creative BioResearch Group, Kyungpook National University, Daegu, 41566, Republic of Korea.
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Kwon M, Jang WY, Kim GM, Kim YH. Characterization and Application of a Recombinant Exolytic GH50A β-Agarase from Cellvibrio sp. KY-GH-1 for Enzymatic Production of Neoagarobiose from Agarose. ACS OMEGA 2020; 5:29453-29464. [PMID: 33225177 PMCID: PMC7676358 DOI: 10.1021/acsomega.0c04390] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 10/22/2020] [Indexed: 05/04/2023]
Abstract
Neoagarobiose (NA2) is the repeating disaccharide unit of agarose and possesses various promising biological activities. To identify an efficient exolytic β-agarase required for NA2 production from agarose, the GH50A β-agarase gene from agar-degrading Cellvibrio sp. KY-GH-1 was overexpressed as a recombinant His-tagged protein using the Escherichia coli expression system. GH50A β-agarase that consists of 797 amino acids was able to produce predominantly NA2 from agarose at an optimal temperature and pH of 35 °C and 7.5, respectively. The enzyme was stable up to 35 °C and within a pH range of 7.0-9.0. The K m, V max, K cat, and K cat/K m values of the enzyme were 26.5 mg/mL, 16.9 U/mg, 25.2 s-1, and 1.2 × 105 s-1 M-1, respectively. The copresence of 5 mM MnSO4 and 10 mM tris(2-carboxyethyl)phosphine (TCEP) resulted in a 2.5-fold enhancement of the enzyme activity. For NA2 production, neoagaro-oligosaccharides (NAOSs) containing NA4-NA18 were preferred over agarose or agaro-oligosaccharides (AOSs) as substrates. NA2 was produced along with minor amounts of agarotriose (A3) after treatment of AOS with the enzyme, indicating that the exolytic digestion of AOS by the enzyme was initiated by releasing A3 from nonreducing ends. Enzymatic hydrolysis of 0.4% agarose (100 mL) using GH50A β-agarase (20 μg/mL) for 4 h under optimal reaction conditions (5 mM MnSO4, 10 mM TCEP, 35 °C, 20 mM Tris-HCl, and pH 7.5) and purification of NA2 from hydrolysis products by Bio-Gel P-2 column chromatography resulted in the recovery of 216 mg of NA2 (∼54% yield from agarose). Altogether, these results suggest that the recombinant GH50A β-agarase is useful to convert agarose to NA2.
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Affiliation(s)
- MiJung Kwon
- Laboratory of Immunobiology,
School of Life Science and Biotechnology, College of Natural Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Won Young Jang
- Laboratory of Immunobiology,
School of Life Science and Biotechnology, College of Natural Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Geon Min Kim
- Laboratory of Immunobiology,
School of Life Science and Biotechnology, College of Natural Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Young Ho Kim
- Laboratory of Immunobiology,
School of Life Science and Biotechnology, College of Natural Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
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